set a system environment variable from a batch command file

http://www.computerhope.com/sethlp.htm     MS-DOS set command help

mordi, what exactly is it that you need to do with your batch file.
Knowiing these details we may be able to offer specific advice.

You should be aware that, if you just set a variable in a batch file that you then run from within Windows, it will only be held in memory for the duration of that batch file.  If used from Full DOS, it will only last for the duration of that session.  Set from somewhere like C:\Autoexec.bat, the variable should remain set for the duration of the Windows session.

Type the single command   SET   in a DOS Window to see the environment variables currently set on your system.

There is another utility file named WINSET.EXE from which you can set Windows environment variables that outlasts the batch file from which the command was run, and should remain for the duration of the Windows session.

Let us know what you are trying to do.

I am talking about system environment variables.Do you know what they are?

http://www.wilsonmar.com/1envvars.htm     Environment Variables
But XP, not 98, has more pre-defined ones like %date% and %time%:
http://kennethhunt.com/archives/000933.html     Environment Variables Windows 2000/XP : Tech Observer
http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/ntcmds_shelloverview.mspx  XP - Command shell overview

mordi.
Yes, I do know. System environment variables are for global use and User environment variables are for the logged on user.  The latter is mostly applicable to Windows NT-based systems or multi-user logons.

Here's some extracts of notes I previously made a while ago which you may find useful.

When setting a path in autoexec.bat or another batch file, I'm sure that there is a maximum limit of 127 or 128 characters.  As I understand it, setting the path from config.sys does not have this limitation.

The Win9x Environment Space is limited, and you could easily exceed this and see an error message "Out of Environment Space".
You can increase the space by adding the following lines:

C:\CONFIG.SYS:
SHELL=C:\WINDOWS\COMMAND.COM /P /E:4096

C:\Windows\SYSTEM.INI under the [NonWindowsApp] section header:
CommandEnvSize=2424

If you set a variable that comprises a path containing spaces
eg: set BILLSPICS=C:\Windows\Profiles\Bill\My Documents\My Pictures
and you want to use the %BILLSDOCS% variable in a batch file, then enclose it in " " like this:
DIR /on /s "%BILLSPICS%\*.jpg" > %TEMP%\BillsJPGs.txt
Preferably, use the DOS names for variables using paths with spaces
eg: set BILLSPICS=C:\Windows\Profiles\Bill\MYDOCU~1\MYPICT~1

If an environment variable contains a directory name ending with a trailing backslash (\)
eg: set dir=c:\folder1\
COMMAND.COM will not accept the CD (change directory) command using the specified directory held in the variable. Avoid using a trailing \ in path variables.

If you redirected some program output that appends a \ to a path, and then tried to SET that as a variable, you COULD HAVE stripped off the trailing backslash on a Windows NT-based system using the following command, but I don't think there is a way in Windows 98:
set STRING=%1
if "%STRING:~-1%"=="\" set STRING=%STRING:~0,-1%

PATH TIP:
To clear all search-path settings other than current directory), use the following syntax:
PATH ;

You shouldn't have to use anything other than autoexec.bat, config.sys, and msdos.sys to set system environment variables, but if you do come upon any limitations then look at utility programs like this:

http://www.codeguru.com/cpp/w-p/win32/tutorials/article.php/c10849/

WINSET.EXE
----------

First of all, beware of rogue versions of Winset.exe:
http://www.pcreview.co.uk/startup/winset.exe.php

Winset Uses:

By Al Fasoldt:
http://aroundcny.com/Technofile/texts/bkwinset98.html

By Eric Phelps:
Winset lets you set environment variables globally (they persist once your batch file ends).
ftp://ftp.microsoft.com/Products/Windows/Windows95/CDRomExtras/AdministrationTools/ApplicationTools/envars.exe
(self extracting .exe - unpack it to its own folder).
Note: Winset cannot be run from FULL DOS.

Other Notes (not sure if they are applicable to Windows 98 as well as 95):
The logon script processor for Windows NT logon scripts does not support setting environment variables in Windows 95. WINSET.EXE is a Win32 console application that overcomes this limitation. When called from a batch file (including an NT Logon script) it sets an environment variable in Window's global environment. Please note that WINSET.EXE does not set an environment variable in the batch file's environment, only Window's global environment. The syntax for WINSET.EXE is the same as the SET command in DOS, with one exception. It won't list all the environment variables set as you would see if you typed the SET command with no parameters.

Bill

I need to change  the system environment variable several times from my command , not only on system startup

My information doesn't only refer to setting the variables at system startup.  That's the reason I mentioned the fact that the SET command run from a batch file within Windows will only last while that DOS window is open, or any other DOS window if the variable has been passed on to it.

That's also the reason I mentioned winset.exe ie. as a way to set environment variables that persist beyond the term of the batch file that called it.

You will find winset.exe in the ..\tools\reskit\scrpting  folder of a Win98se CD.  The file's properties describe the program file as "WINSET - Sets variables in the Windows 95 master environment".  Yes, I know it says "Windows 95", but it works in Windows 98/98se or it wouldn't be on the CD.

WINSET [variable=[string]]

variable  Specifies the environment-variable name.
string     Specifies a series of characters to assign to the variable.

Try it out and compare the results with the SET command when used from a batch file within Windows.
Get the batch file to set one variable using the SET command, and another variable using WINSET then exit.
Run a 2nd batch file and have it show the current environment variables using the SET command with no parameters.
The variable set using WINSET will have persisted, while the one created with the SET command will have been lost.
If you need to change the variable several times, then just clear the variable's value and reset it to another value.

TEST1.BAT - Run this first

@echo off
:: Clear any existing values for both variables
set VAR1=
set VAR2=
winset VAR1=
winset VAR2=
::
set VAR1=Created with Set (VAR1)
winset VAR2=Created with Winset (VAR2)
::
exit


TEST2.BAT - Run this after TEST1.BAT terminates and closes the DOS window

@echo off
echo.
echo Environment Variables shown by the 'SET' command:
echo.
set
echo.
echo Do you see VAR1 listed above?
echo No, because it was set using the 'SET' command.
echo VAR2, however, was set using the 'WINSET' command.
echo.
echo Now 'echoing' the variables ...
echo.
echo Value of VAR1: " %VAR1% " - Do you see anything?
echo Value of VAR2: "%VAR2%" - Bet you see this value!
echo.
echo press any key to end ...
pause>nul
:: Clear variables again before terminating
set VAR1=
set VAR2=
winset VAR1=
winset VAR2=
exit

OK, so maybe that doesn't quite do what you need, but try it anyway.

mordi
Have you had the chance to test my suggestions out?

Sorry for thr delay.
I need it for windows XP and NOT for windows98, by mistake i entered the wrong os TOPIC.
What i need is as you said before, to set Windows environment variables that outlasts the batch file from which the command was run, and should remain for the duration of the Windows session.

Hi mordi

set VARIABLENAME=Value

Related info:
http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/setlocal.mspx

http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/ntcmds_shelloverview.mspx
http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/environment_variables.mspx
http://support.microsoft.com/default.aspx?scid=kb;en-us;310519

1. Log on with  admin rights (any user can modify a "user" variable, but not a "system" one)
2. Right-click "My Computer" then click "Properties"
3. Click the Advanced tab
4. Click Environment variables
5. Options: "user" or "system" variable:
   (a) New variable - to add a new variable name and value <------- This one **
   (b) existing variable > Edit to change variable name or value
   (c) existing variable > Delete to remove an existing variable

http://vlaurie.com/computers2/Articles/environment.htm (With screenshots and additional info)

Windows, DOS, and other operating systems - interest value :
http://en.wikipedia.org/wiki/Environment_variable
http://www.wilsonmar.com/1envvars.htm

Hope this helps
Bill

Sorry callrs, I ended up re-quoting links you provided earlier, but how did you know mordi was talking about Windows XP way back then? ;-)

Again it doesn't answer my question.
As i stated before, i need something like winset, to change a system variable from a batch file comand program.